TLR7 and rheumatoid arthritis: Given the observations that TLR7 knock-out mice displayed attenuated disease in murine collagen-induced arthritis (CIA) model [27] and intra-articular knockdown of TLR7 by an adenoviral antisense resulted in decreased disease activity in the rat CIA model [28], our observation that TLR7 is an upstream regulator of RA differentially expressed genes, further validates TLR7 as a potential target for RA.